The overall objective of this contract is to reconfirm preliminary data onthe influence of specific aspects of animal housing upon the nutritional, hormonal, and immunological status of normal and tumor-bearing mice. Specific objectives are: To generate specific data to confirm the influence of cage population density upon food consumption, caloric intake, anorexia, stress, and tumor behavior. To validate the differences in the physiological status of mice housed in standard plastic cages with that of mice housed in hanging wire bottom cages. Ton confirm that the presence of males, and their pheromones, produce physiological responses in females that are capable of perturbing sensitive experimental parameters. Evidence for the pheromonal stimulation of males by females will also be confirmed.